Northern Crown ascends to its highest point in July

Contributed | BDN

Contributed | BDN

By Clair Wood Special to the NEW, Special to the BDN •July 7, 2010 5:53 pm

Corona Borealis, the Northern Crown, is a small bright circlet of stars located between Hercules and Bootes. It reaches its highest point in the sky in early July. The Greeks called it a wreath, the Australian aborigines a boomerang, and native Americans a camp circle or the Celestial Sisters. The common legend of antiquity was that the crown was a wedding present to a princess of Crete, a complicated story involving several romantic liaisons and the Minotaur, a monster that was half man, half bull. Its brightest star is Alphecca, the jewel of the crown, and that is 75 light years from Earth and has a luminosity greater than 52 Suns.

Focus on the Planets

Three planets, Saturn, Mars, and Venus, are lined up along a descending slanting line in the west as darkness falls.

Mercury does not appear until mid-month when it may be found to the lower right of Regulus, low in the west a half hour after sunset.

Venus is by far the brightest object in the west an hour after sunset as it continues to draw nearer to Earth. Venus and Regulus are within a degree of each other on July 9.

Mars starts the month to the upper left of Venus and not too distant from Regulus, whose blue-white contrasts nicely with the reddish-orange of Mars.

Jupiter rises in the east shortly after midnight on July 1 and earlier each night thereafter. By dawn Jupiter has moved toward the south, where it is the brightest point of light in the sky affording a good opportunity to view the surface features and the movement of its four moons about it. On July 5 and 8 all four moons are aligned on one side of the planet.

Saturn is the pale, golden point to the upper left of Mars on July 1. The ring system still disappoints, tilted only 3 degrees to our line of sight, but this affords a good opportunity to view its moons, particularly Titan.

Uranus is easily spotted as a blue-green disk by binoculars. Locate Jupiter in your field of vision and Uranus is to the right.

Neptune is high in the southeast after midnight, where it is revealed as a blue-gray disk by telescope.

July Events

9 Venus is situated about one degree from Regulus an hour after sunset. Mars is located far to the upper left of the duo.

11 New Moon, 3:40 p.m. If you happen to be in Tahiti or on Easter Island today you will see a total eclipse of the Sun.

13 The Moon is at perigee, or closest approach to the Earth.

15 Looking west an hour after sunset you will see Saturn, Mars, Venus, Regulus and possibly Mercury in descending order with the thin crescent Moon to the lower left of Mars.

18 Moon in first quarter, 6:11 a.m.

20 The Sun enters Cancer on the ecliptic.

22 The Sun enters the astrological sign of Leo but astronomically has just entered Cancer.

26 Full Moon, 9:36 p.m. The full Moon of July is called the Hay Moon, Strawberry Moon or Thunder Moon.

28 This is the pear night for the Delta Aquarid meteor shower. Normally a density of 15-20 meteors per hour could be expected, but the nearness of the full Moon will likely cut this to around 5 per hour.

29 The Moon is at apogee for the second time this month.

31 Saturn and Mars are paired together high in the west after sunset with Venus and Mercury strung out to the lower right. Sunrise, 5:19 a.m.; sunset, 8:03 p.m.